Institute of Phytopathology and Plant Physiology (IFFIVE-INTA), X5020ICA Córdoba, Argentina.
J Plant Physiol. 2010 Dec 15;167(18):1622-6. doi: 10.1016/j.jplph.2010.06.024.
Oxidative stress responses generated by paraquat (PQ), an herbicide that triggers an oxidative stress reaction in leaves, were studied in non-arbuscular mycorrhizal (non-AM) and in arbuscular mycorrhizal (AM) soybean plants inoculated with Glomus mosseae (Gm) or Glomus intraradices (Gi). Some oxidative stress symptoms were evident in non-AM after 6 d of PQ application on leaves. Oxidative damage, measured as malondialdehyde content (MDA), was significantly higher, and although no changes were evident in total catalase (CAT, EC 1.11.1.6) and total superoxide dismutase (SOD, EC 1.15.1.1) activity, total ascorbate peroxidase (APX, EC 1.11.1.11) activity was significantly reduced. These effects were correlated with a significant decrease in growth parameters. By contrast, in both AM plants, foliar MDA content was reduced or unaltered and, interestingly, after PQ stress, its level was unchanged and significantly lower than in PQ non-AM plants. Unlike PQ stress in non-AM plants, total APX activity was unaltered or induced by AM plants, while total SOD activity was unchanged and no consistent effects were detected in total CAT activity. All these events coincided with no changes or a significant increase in growth parameters. Since oxidative stress is a common phenomenon triggered by several environmental stresses, these results highlight the importance of mycorrhizal fungi in oxidative stress regulation as a general strategy to protect plants from abiotic and biotic stress.
百草枯（PQ）是一种除草剂，会在叶片中引发氧化应激反应，研究了非丛枝菌根（非-AM）和丛枝菌根（AM）大豆植株在接种摩西管囊霉（Gm）或内氏根霉（Gi）后的氧化应激反应。在叶片施加 PQ 后的第 6 天，非-AM 中出现了一些氧化应激症状。氧化损伤，用丙二醛含量（MDA）来衡量，显著升高，尽管总过氧化氢酶（CAT，EC 1.11.1.6）和总超氧化物歧化酶（SOD，EC 1.15.1.1）活性没有明显变化，但总抗坏血酸过氧化物酶（APX，EC 1.11.1.11）活性显著降低。这些影响与生长参数的显著下降有关。相比之下，在两种 AM 植物中，叶片 MDA 含量降低或不变，有趣的是，在 PQ 胁迫后，其水平不变，且明显低于 PQ 非-AM 植物。与非-AM 植物中的 PQ 胁迫不同，总 APX 活性在 AM 植物中未改变或被诱导，而总 SOD 活性不变，总 CAT 活性未检测到一致的影响。所有这些事件都伴随着生长参数的不变或显著增加。由于氧化应激是由几种环境胁迫引发的常见现象，这些结果强调了菌根真菌在氧化应激调节中的重要性，作为一种保护植物免受非生物和生物胁迫的一般策略。
